Adjustable spanner

ABSTRACT

Monkey wrench, of the type built up of a fixed clamp ( 1 ) solidary with the grip and a mobile jaw ( 2 ) provided with a rack ( 3 ) in which an operation shaft ( 5 ) is engaged, and in which the drive nut ( 4 ) is disposed on a shaft ( 5 ) built up of a flexible elastomer material, remaining the mentioned shaft ( 5 ) configured by a compact cylindrical body with a diameter in correspondence with the respective installation housing ( 6 ); and because in the assembly disposition of the mentioned shaft ( 5 ) it remains slightly deflected, exercising a pushing of the nut ( 4 ) towards the rack ( 3 ) of the mobile jaw ( 2 ), with the possibility to separate the mentioned nut ( 4 ) regarding the mentioned rack ( 3 ) of the mobile jaw ( 2 ), by forced displacement of the nut ( 4 ) against the action of the indicated shaft ( 5 ).

The monkey wrenches consist in a set built up of a fixed clamp thatforms a body of one only piece with the tool handle and a mobile jawthat is moveable in approach and separation regarding the mentionedfixed clamp, this mobile jaw is provided with a toothed rack, with whichit engages a drive worm that is mounted in such a way it can turn freelyon a shaft.

Conventionally, the mentioned drive worm is disposed on a rigid metallicshaft, incorporating, in one end of the worm housing, a pusher spring,so as to avoid this way the axial looseness of the worm. The movable jawremains nevertheless with a certain looseness in the gear with regard tothe worm, which causes undesirable noises when moving the key.

To avoid that problem of the looseness of the mobile jaw, a solution isknown. It consists in preparing the drive worm divided into two axiallyconsecutive parts, with a reduction of the separation between the filletcarvings of the gear thread with the mobile jaw, in the area of thementioned worm division, with which, by virtue of the pushing of thespring, which eliminates the axial looseness the contact of the lateralparts of the fillets of the threading of one of the two parts of theworm components is produced, against the lateral faces of the rack teethof the mobile jaw, avoiding with it the looseness of the mentionedmobile jaw. The execution and assembly of this solution is howevercomplicated, being it moreover expensive to carry out the worm in twoindependent pieces.

A solution is also known to allow the separation of the drive wormregarding the gear with the mobile jaw, so as to allow the quickmovement of the mentioned mobile jaw; in the way it is indicated in theU.S. Pat. Nos. 1,402,686 and 2,724,301. With this same concept, theChinese patent 92242425 offers a solution according to which a helicalspring is disposed as the shaft of the worm. It is compressed betweentwo extreme balls that support against some inclined planes, with which,when pulling at the worm in the sense of their separation with respectto the rack of the mobile jaw, the sliding of the extreme balls of theshaft along the inclined supporting planes, makes that the spring thatforms the shaft is compressed axially at the same time as it movestogether with the worm in the separation sense respect to the rack ofthe mobile jaw, allowing this way the liberation of the mobile jaw withregard to the worm.

French Patent 2.126.534 discloses a solution in which the worm is forcedby a flexible element to be always in engagement with the rack of themobile jaw; this flexible element allowing that the worm may be pushedout of engagement with the rack (3).

In all the embodiments already known, the construction is in factexpensive and the assembly really difficult. Furthermore, in order toavoid that the worm is moved excessively in transverse direction, theflexible element must be complemented with a shaft, which is in factformed in the support of the worm.

In accordance with the present invention a key is proposed which adoptsa new assembly solution for the drive worm, to be able to join the twopreviously mentioned functions, eliminating the looseness and with thepossibility to liberate the mobile jaw, obtaining some more advantageousconstructive and functional characteristics than with the solutions upto now developed.

The new solution consists in preparing the drive worm on a flexibleshaft of elastomer material, according to an assembly disposition sothat this shaft, because of its flexion, pushes the mentioned drive wormtowards the mobile jaw.

This way, a radial pressure of the drive worm is reached, against themobile jaw, which, in combination with the inclination of the flanks ofthe teeth and the gear threads between both pieces, cancels theslackness of the gear, reaching this way a certain fixation of themobile jaw, so that undesirable noises do not take place.

The own flexibility of the shaft allows, on the other hand that thedrive worm can be moved in a forced way in the opposite sense of itspressure against the mobile jaw, thanks to the elastic deformation ofthe shaft.

This allows to liberate the mobile jaw from its connection with thedrive worm, so as to leave this mobile jaw free from a quickdisplacement in the approaching or separating sense regarding the fixedclamp, with which the adjusting of the wished opening of the key iseasier and quicker.

In combination with that displacement possibility of the drive worm,until the release of the gear between the worm and the mobile jaw isreached, a realization of the teeth and of the gear thread is foreseenwith a lateral one according to some inclined planes, with aninclination orientated in the sense of approach of the mobile jawtowards the fixed clamp.

With it such a disposition is obtained that, by means of a simple pushof the mobile jaw towards the fixed clamp, an elastic jump of the rackteeth of the mentioned mobile jaw takes place regarding the threads ofthe drive worm, due to the displacement in the separation sense to whichthe mentioned worm is subjected when sliding the inclined lateral planeof its fillets on the inclined lateral plane of the rack teeth of themobile jaw, reaching this way a ratchet effect that allows the quickclosing of the key by means of only the push of the mobile jaw towardsthe fixed clamp.

This particularity supposes a great advantage for the handling of thekey, since it allows its quick closing for its approach to the measureof the object on which it has to act, being able to carry out thatclosing in an easy way, even in uncomfortable and difficult positions,since it is only necessary to push the mobile jaw towards the fixedclamp, which is executable by the user with a single hand, allowing thisway the performance of the wrench in a much easier way in places wherethe access with both hands at the same time is difficult or impossible.It is worth pointing out in this respect that the approaching movementof the jaws is the one which particularly interests in a quick way whenusing the wrench, since the wrench should be prepared with asufficiently open width, to insert it on the actuation element, on whichit is adjusted once inserted; while to retreat the wrench, once carriedout the performance, only a slight separation of the jaws is necessaryto be able to retire the wrench without difficulty.

The liberation of the mobile jaw regarding the gear with the drive worm,by the movement of the latter, allows that this mobile jaw can even beextracted out of its housing assembly in the wrench, in combination withwhich a realization with the provided mobile jaw of a plane front in oneof its parts and with incorporation of a toothed piece in the opposedfront, in such a way that, by means of the extraction of the mentionedmobile jaw out of its assembly housing, the position of the same can beinverted regarding the fixed clamp, allowing this way the adaptation ofthe wrench to act on polygonal elements and also to act on cylindricalelements.

The flexible elastomer shaft of the drive worm is built up of a compactcylindrical body of a diameter in correspondence with the assemblyhousing of the wrench, being the fixed disposition of the mentionedshaft foreseen in a preferable way by means of the gluing of its ends inthe assembly housing; although also, without modifying the essential ofthe invention, the mentioned shaft body can incorporate a threaded headin a solidary way joined in one end, for the fastening by means of athreaded assembly in the corresponding housing.

The shaft body can moreover incorporate, in an optional way, inside theelastomer material, reinforcements with the help of bars or metallicplates, by means of which at the same time the flexion strength of thementioned shaft can be reinforced.

In view of all this, the mentioned monkey wrench object of the presentinvention indeed has some very advantageous characteristics as comparedto the conventional monkey wrenches.

FIG. 1 represents a monkey wrench in agreement with the scope of theinvention.

FIG. 1a is an enlarged partial view corresponding to the end where thehead of the wrench is situated.

FIG. 2 is a corresponding profile of the same extreme part of the wrenchrepresented in the previous figure.

FIG. 3 is a section lateral view and at greater scale of the wrenchhead.

FIG. 4 is a detail in an enlarged section of the drive worm assembly ofthe wrench in its disposition on the corresponding flexible shaft,according to a non limitative example of a practical realization.

FIG. 4a is a detail as the previous one, with the flexible shaft of theworm provided with bushings incorporated at the ends.

FIG. 5 is a similar detail of the assembly of the drive worm of thewrench in its disposition on the corresponding flexible shaft, accordingto another realization example.

FIG. 6 is a traverse section of the flexible shaft according to theindication VI—VI pointed out in the detail of the previous figure,having represented some radial arrows around A, B, C, and D whichindicate the flexion and rigidity directions of the mentioned shaft inthis realization.

FIG. 7 is a detail in an outline that shows the radial deviation in theassembly between the half part of the flexible shaft which incorporatesthe drive worm and the ends of the mentioned shaft.

FIG. 8 is an outline that represents the sliding gear towards one sidebetween the rack of the mobile jaw and the drive worm.

FIG. 9 is a representation as the one of the previous outline, beingindicated in “dot and dash line” the position of the drive worm and ofthe mobile jaw in the jump of the gear between both when the mobile jawis pushed.

FIG. 10 is a sectional lateral view of the wrench head, according to arealization of a reversible assembly of the mobile jaw.

FIG. 10a is a representation to a smaller scale of the wrench head inthe realization of the previous figure, with the drive worm disengagedregarding the mobile jaw.

FIG. 10b is a representation as the previous one, with the mobile jawinverted in its position regarding the fixed clamp.

The invention refers to a monkey wrench of the ones that include a fixedclamp (1) forming an only piece with the body of the handle and a mobilejaw (2), moveable in the approach and separation senses with regard tothe mentioned fixed clamp (1), possessing the mentioned mobile jaw (2) atoothed rack (3), with which a drive worm (4) is connected, prepared infree turn on a shaft (5), so that the turning operation of the mentionedworm (4) causes the displacement of the mobile jaw (2).

In accordance with the invention, the drive worm (4) is disposedincorporated on a shaft (5) of elastomer material, such as rubber orsimilar, so that the mentioned shaft (5) is flexible, being foreseen itsdisposition according to an assembly with tendency to push the worm (4)towards the mobile jaw (2).

That pushing effect of the worm (4) towards the mobile jaw (2) isreached by the flexibility of the shaft (5) itself and its assemblydisposition, since in the assembly the mentioned shaft (5) is disposedin such a way that its ends are included in a housing (6) whoselongitudinal shaft (11) is located with regard to the mobile jaw (2) ata distance somewhat smaller than the own central shaft (12) of the worm(4), in the way it is represented in FIG. 7, with which the shaft (5)remains exercising, a push of the mentioned worm (4) towards the mobilejaw (2), because of its flexible recovery effect.

This way, the worm (4) remains pressed against the mobile jaw (2), withwhich the looseness of the gear between both pieces is cancelled, beingthis way the mobile jaw (2) with a fixation that avoids its freemobility in the clearance, with which a greater precision is obtained aswell as a softness in the displacement of the mentioned mobile jaw (2),avoiding the noises because of the looseness of the assembly.

In a conventional way, the worm (4) is also pushed axially by a spring(7), as it can be observed in FIGS. 4 and 5, with which the clearance inthis axial sense is also eliminated, also avoiding this way that noisestake place because of the looseness in that axial sense.

The flexible shaft (5) is built up of a compact cylindrical body, with adiameter in correspondence with the assembly housing (6) in the wrench,determining the mentioned cylindrical body with a very refined externalsurface, so that in the disposition of the worm assembly (4) the lattercan slide on the mentioned shaft (5), allowing a gentle operation of thenecessary rotation for the displacement of the mobile jaw (2).

The assembly of the mentioned shaft (5) is established with a fixationof its ends in the corresponding housing (6), for which, according to apossible practical realization, it is foreseen that the extreme parts ofthe mentioned shaft (5) remain fixed in the housing (6) by means of itsgluing.

This gluing fixation can be carried out directly between the ends of theshaft body (5) and the housing wall (6), in the way it is represented inFIG. 4, in which case it is necessary to use glue that is compatiblewith the elastomer material that builds up the mentioned shaft body (5).

According to a possible realization variant, at the ends of the shaft(5), some bushings (8) can be incorporated, in the way it is representedin FIG. 4a, the mentioned bushings (8) can be of any rigid material thatallows the use of all kind of glues, for example for metallic material;to establish the shaft fixation (5) in such a case, by means of thegluing of the mentioned bushings (8) on the wall of the housing (6).

In such a realization the bushings (8) are incorporated preferably bymeans of their integration in the moulded production of the syntheticbody of the shaft (5), being foreseen that the mentioned bushings (8)are provided with holes and/or grooves so that the elastomer material ofthe moulded body is inserted in them, being this way an only monoblockbody. The mentioned bushings (8) could however be incorporated on theends of the shaft (5), by means of any other solidarization technique,without altering the essentiality of the invention.

According to another possible realization, a threaded head (13) can beincorporated to the synthetic body of the shaft (5) which is solidarilyunited at an end, allowing this way the attachment of this shaft (5) bymeans of an assembly threaded into the housing (6), in the way it isrepresented in FIG. 5.

On the other hand the worm (4) is foreseen with some widenings at theend of its axial passage hole of the shaft (5), with which the mentionedends of the worm (4) remain with a clearance regarding the mentionedshaft (5), allowing a certain radial flexion of the shaft body (5) inthose areas in the assembly disposition.

The mentioned radial flexion possibility of the shaft (5), allows theforced displacement of the worm (4) in the sense of its separationregarding the rack (3) of the mobile jaw (2), being able to remain thisworm (4) completely disjointed from the engagement with the mentionedrack (3) of the mobile jaw (2), being then the mentioned mobile jaw (2)free of displacement, in such a way that it can be moved in a quick wayand without the need of the revolvable drive worm (4), for the approachor separation regarding the fixed clamp (1).

To facilitate the manipulation of the worm in any event (4),both in itsrevolvable operation for the slow mobility of the mobile jaw (2), and inthe radial displacement for the quick mobility of this mobile jaw (2),the lower part of the housing (9) defines a bevel (10) in its externallateral faces. This allows a free sliding of the user's fingers in theoperation, facilitating this way the manipulation.

In combination with the possibility of a radial displacement of the worm(4) by the elastic flexion of the shaft (5), a realization is foreseenso that the helical ribs of the worm (4) and the corresponding rackteeth (3) of the mobile jaw (2) determine some reciprocal inclinedplanes (21), in one of the sides, as it can be observed in FIG. 3.

With it, the support between the indicated helical ribs of the worm (4)and the mentioned teeth of the mobile jaw (2) results in a slidingeffect in the sense of approach of this mobile jaws (2) towards thefixed clamp (1), which allows that, by means of the pushing of themobile jaw (2) towards the fixed clamp (1), the closing of the wrenchcan be carried out immediately, due to the sliding jump of the teeth ofthe mobile jaw (2) on the helical ribs of the worm (4) in combinationwith the radial displacement of the worm (4), by the pushing that thisone suffers in consequence in the radial sense, giving rise to a ratcheteffect.

The liberation of the mobile jaw (2) by the forced radial displacementof the worm (4), allows that the mentioned mobile jaw (2) can even beextracted out of its assembly housing in the wrench.

In combination with it, a realization of the mobile jaw (2) is foreseenprovided with a flat front (15) in one of its parts and withincorporation of a toothed piece (16) in the opposed part, with which,by means of the extraction of the mentioned mobile jaw (2) of itsassembly housing, its position can be inverted, in the way it isrepresented in FIGS. 10a and 10 b, allowing this way the adaptation ofthe wrench to act on polygonal elements, by means of the dispositionwith the flat front (15) opposed to the fixed jaw (1), or to act oncylindrical elements, by means of the disposition with the piece (16)faced to the fixed jaw (1), in which a corresponding toothed front (17)is foreseen to such an effect.

In a particular way, the toothed piece (16) is foreseen according to asliding assembly, acted by a spring (18) towards a fixed position, withthe purpose of facilitating the operative disposition of the wrench onthe cylindrical elements of application with the necessary adjustment sothat the performance of the wrench is effective.

The flexible shaft (5) of assembly of the worm (4) can be of anyelastomer material that allows an appropriate elasticity and which atthe same time has the necessary rigidity to support the worm (4) in itsoperative disposition, having carried out satisfactory tests, to such aneffect and in connection with a disposition of the mentioned shaft (5)directly glued with regard to the assembly housing (6), with arealization of the mentioned shaft (5) with the help of naturalelastomer materials, such as rubber or synthetic material as for exampleacryl-nitrile-butadiene “NBR”, or chloroprene polymers “CR”; but ingeneral, practically, the realization of the mentioned shaft (5) can becarried out by any kind of elastomers, such as silicone, “VMQ”, fluoricsilicone “FUMQ”, polyacrylates “ACM”, or those of the type “HNBR”,“FKM”, “EPDM”, etc . . . .

The determination of the shaft (5) by a cylindrical body of an onlypiece, allows its obtaining by simple cutting starting from a continuousbody; but in a same way the acquisition can be by moulding, being ableto adapt the conformation that is required in each case, even withdifferent sections as it suits to the application disposition in thewrench.

This does not suppose an alteration of the essentiality of the object,the mentioned cylindrical body of the shaft (5) can be supplemented withfalse accessory elements, such as the extreme bushings (8) themselvesfor the gluing into the housing (6), or other pieces of a similarfinish, as well as a central bushing (19) to facilitate the revolvablesliding of the worm (4), or flexible elements, such as bars or strips(20) integrated inside the elastomer material, to reinforce theresistance and the strength of the flexibility of the elastomer materialin the way it is represented in FIG. 5.

In the case of inclusion of a flat strip (20) in the inside, the flexionof the shaft (5) is guided, whenever, considering the directionsindicated in FIG. 6, the flat strip (20) can only bend according to thedirection A-B, determining on the contrary undeformable rigidity in thedirection C-D. This makes that the flexion of the shaft (5) can beestablished only to act in the sense in which the mobile jaw (2) isformed, being on the contrary rigid in the perpendicular sense, whichavoids that an undue flexion of this shaft (5) can take place in thesense C-D by the pushing exercised when the worm (4) is being operatedby the user.

What is claimed is:
 1. A Monkey wrench, of the type comprising a handle,a fixed jaw integral with the handle, a mobile jaw provided with a rack,the mobile law slidingly engaged in the handle, and a drive worm foroperative connection with the rack, said drive worm held in connectionwith the rack by the flexible element being displaceable so that thedrive worm can be disconnected from operative connection with the rack,the monkey wrench being characterised in that: said flexible element isa shaft comprising a flexible elastomer material, said shaft having twoends and further comprising a cylindrical body received in a bore of ahousing portion of the handle; wherein in the assembly of said shaft inthe handle, said shaft is slightly bent whereby the drive worm is biasedagainst the rack of the mobile jaw, said drive worm being displaceableout of engagement with said rack by a pressure applied against the biasaction of said shaft.
 2. Monkey wrench according to claim 1, furthercharacterized in that both ends of said shaft are received in said borein the housing portion; and said shaft is fixed to the housing portionby means of gluing each end of said shaft to a wall of the bore in whichit is received.
 3. Monkey wrench, according to claim 1, furthercharacterized in that the shaft includes two bushings, each bushingbeing fixed to corresponding ends of the shaft; and each bushing beingglued to a wall of the bore.
 4. Monkey wrench, according to claim 1,further characterized in that said shaft includes a threaded head at oneof said two ends, the threaded head being engaged in a correspondingthread in the bore.
 5. Monkey wrench, according to claim 1, furthercharacterized in that said shaft includes a flat strip embedded in theflexible elastomer material whereby the flat strip and the shaft can bedeflected in a first lateral direction thereby allowing the drive worm(4) to be moved out of engagement with the rack; said shaft being rigidin a second lateral direction, perpendicular to the first lateraldirection.
 6. Monkey wrench, according to claim 1, further characterizedin that the cylindrical body further comprises a refined externalsurface over which the drive worm is rotatable slidable.
 7. Monkeywrench, according to claim 1, further characterized in that the shaftincludes on a central portion thereof an external bushing on which thedrive worm is rotatably supported.
 8. Monkey wrench, according to claim2, further characterized in that the shaft includes two bushings, eachbushing being fixed to corresponding ends of the shaft; and each bushingbeing glued to a wall of the bore.